Author: Vito Hernandez
Hernandez, Vito, 2025 Early human dispersals and occupations of Pleistocene Southeast Asia: A micro-geoarchaeological approach, Flinders University, College of Humanities, Arts and Social Sciences
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This doctoral thesis uses micro-geoarchaeology to advance our understanding of Pleistocene human dispersals and occupations in Southeast Asia where the depositional environments of many key fossils and artefacts remain poorly understood. This is mainly due to the complex site formation processes in the tropics, which has led to uncertainties with fossil and artefact chronologies and difficulties situating Pleistocene humans within specific environments. These challenges have resulted in unresolved questions regarding the timing, nature and drivers of human dispersals in the region during this early time period.
To address this gap and further contribute to advancing tropical geoarchaeology, this PhD research reviews the microstratigraphic studies of Pleistocene sites identified as critical to our understanding of early human dispersals in Southeast Asia, applies microstratigraphy to two significant sites, and identifies baseline microstratigraphic data that could facilitate interpretations of its fossil and archaeological records. Microstratigraphic methods (micromorphology, SEM-EDS, magnetic susceptibility, total organic carbon) were employed to study Mata Menge (~0.7–0.3 Ma) in Flores Island (Indonesia) and Tam Pà Ling (~52–30 ka) in northeastern Laos. These sites were chosen because they are chronologically, geomorphologically and archaeologically different from each other, permitting an exploration of the historical narrative of Early–Middle Pleistocene archaic humans and Late Pleistocene modern humans in the region. These studies mark the first use of microstratigraphy on these two sites critical to understanding human evolution in the Far East.
The microstratigraphic analyses of Mata Menge and Tam Pà Ling reveals distinct depositional environments contributed to the preservation of fossils. At Mata Menge, fossils were deposited in a low flow (Ca-rich) streambed under increasingly dry conditions. At Tam Pà Ling, fossils, alongside combustion features, were preserved in alkaline cave sediments in a moderately humid environment. This study shows Pleistocene human dispersals in Southeast Asia occurred in a predominantly tropical climate. During the Middle Pleistocene, the dispersals of archaic humans such as Homo erectus and Homo floresiensis were driven by drier climates, driving their spread towards riverine, palustrine and coastal settings. During the Late Pleistocene, modern humans such as Homo sapiens, and possibly Denisovans, demonstrated greater adaptability to climate changes, exhibiting greater agency compared to archaic humans when choosing environments for refuge and to exploit resources. These findings suggest that during the Pleistocene climate was a major driver of human dispersals, although Late Pleistocene humans also regarded topography and resource accessibility closely when moving to nearby familiar landscapes.
This thesis underscores the potential of microstratigraphy to study the Pleistocene human evolutionary record of Southeast Asia, showcasing its effectiveness in reconstructing the depositional environments and understanding the diagenetic processes that control fossil preservation. Additionally, this thesis highlights the need for a comprehensive approach to geoarchaeological research in the region. It recommends the application of targeted sampling methodologies driven by a microstratigraphic framework, the integration of multi-scalar geoarchaeological and advanced scientific analyses, and the training of more local geoarchaeologists to maximise the extraction of micro-bio and -geoarchaeological data and ensure more effective preservation and interpretation of the human evolutionary record. This PhD thesis contributes to the growing body of geoarchaeological studies in Southeast Asia, offering insights into the complex dynamics of Pleistocene humans and their environment as they dispersed through the region.
Keywords: Hominin, Southeast Asia, Pleistocene, Human Evolution, Geoarchaeology
Subject: Archaeology thesis
Thesis type: Doctor of Philosophy
Completed: 2025
School: College of Humanities, Arts and Social Sciences
Supervisor: Mike W. Morley